The present invention relates to electrically powered wheel chairs and to a device and a method for converting a collapsible portable manual wheel chair to a collapsible portable electrically powered wheel chair.
Prior art devices and methods for converting portable manual wheel chairs to electric wheel chairs are shown in U.S. Pat. Nos. 3,351,148, 3,893,529, and 3,896,891. These prior art devices and methods typically include electric motor powered drive shafts which drive the conventional large rear wheels of the wheel chair to propel and steer the wheel chair.
The prior art has also provided a wide variety of power wheel chairs such as shown in U.S. Pat. Nos. 3,376,944, 3,749,192 and 3,807,520. These power wheel chairs are typically not usable as portable wheel chairs, since they are not adapted to be readily taken apart and collapsed manually in a short time period without the use of tools. This disadvantage limits the use of such electric wheel chairs, since they are not satisfactory for persons who want an electric wheel chair which may be readily manually collapsed and transported by automobile.
The present invention departs from these and other prior art devices and methods by providing a device and a method for converting a collapsible portable manual wheel chair to a collapsible portable power wheel chair without relying upon use of the large rear wheels of the manual wheel chair. According to the present invention, the large rear wheels of the manual wheel chair are removed and replaced with a collapsible portable electric drive unit which does not materially detract from the portability of the wheel chair. This is accomplished by providing a drive unit which includes a left drive wheel assembly, a right drive wheel assembly, a center battery carrier assembly, and a control device. The left and right drive wheel assemblies each include a ground engaging drive wheel and an electric motor drivingly connected to the wheel.
The left and right drive wheel assemblies are each removably connected to the center battery carrier assembly. The left and right drive wheel assemblies and the battery carrier assembly are then removably connected to the wheel chair, and the control device is mounted on the wheel chair and is electrically connected to the left and right drive wheel assemblies.
When the converted electric wheel chair is to be collapsed such as for transportation by an automobile, the left and right drive wheel assemblies and the center battery carrier assembly are manually disconnected from the wheel chair frame. The wheel chair frame is then collapsed, and, since the large rear wheels of the wheel chair are removed, the collapsed electric wheel chair frame is smaller in size than the original manual collapsed wheel chair frame. The left and right drive wheel assemblies are then each manually disconnected from the battery carrier assembly and from one another. This results in three portable light weight assemblies which can easily be placed in the trunk of an automobile or in any other carrier for convenient transportation.